1. Field of the Invention
This invention relates to a method and apparatus for providing a coating on irregular surface means of a workpiece.
2. Prior Art Statement
It is known in the art to provide a coating, such as, of a nonmetallic liquid primer, on irregular surface means of a workpiece by spraying a liquid film of a liquid coating material on the irregular surface means and then drying the liquid film to solidify same and define the coating. It is also known to provide further successive coatings on such irregular surface means also by spraying and drying as mentioned. However, in applying a liquid coating material by spraying there are the usual problems of clogged spray nozzles and difficulty of controlling the thickness of the sprayed liquid film yet without allowing running of the sprayed liquid. Further, spray coating does not assure complete coverage of all portions of an irregular surface means.
It is also known to provide a coating of a liquid coating material on irregular surface means of a workpiece by dipping the entire workpiece in the liquid coating material. However, this technique usually results in excess coating material being used and often requires special drying equipment and additional drying time before the workpiece can be processed further.
It has also been proposed to make a wear member for use between a pair of relatively movable components of a railway vehicle and wherein the wear member is comprised of metal support means defined by a metal sheet having a planar surface and a grid-like metal structure fixed against the planar surface and with ultra high molecular weight polymeric material attached to the support means so that the grid-like metal structure serves as a means for attaching the polymeric material to the metal sheet of the support means while providing integral reinforcement of the polymeric material and as disclosed in U.S. patent application Ser. No. 27,340 now U.S. Pat. No. 4,238,039, issued Dec. 9, 1980. However, prior to bonding the polymeric material in position as disclosed in the above-mentioned patent application, it is common practice with certain types of grid-like structures to spray coat the irregular surface means defined by the planar surface of each metal sheet and its grid-like structure with a suitable primer followed by drying and then followed by spray coating over the primer with a suitable urethane base material again followed by drying before performing further process steps. However, these spray coating steps are all prone to the difficulties mentioned above.
It is also well known in the art to provide a method and apparatus for coating irregular surface means of a workpiece, such as a printed circuit board, or the like, which has various components and lead pins protruding therefrom utilizing so-called wave soldering apparatus and as disclosed in U.S. Pat. No. 4,208,002.